The human microbiome is closely connected to our immune system. Our bodies have to be able to keep the bacterial populations in the gut in check, but also ensure we maintain a robust and healthy microbiome to promote good health. Researchers have now learned more about the antiviral activity of molecules that are generated by bacteria in the gut microbiome. While this work was conducted in a cell culture model, it shows that some metabolites that are produced by microbes in the gut could help fight COVID-19 or other viral infections. The findings, which compliment a previous study referenced in the video below, have been reported in mSphere.
With advances in computational tools and genetic technologies, scientists have been able to study the vast array of microbes, including bacteria, archaea, viruses, and fungi, that call the human gastrointestinal tract home. Many specific microbes have been associated with disease, and researchers are just beginning to decipher the details of those relationships. All of those microbes carry their own genomes and can generate their own proteins, many of which can act on the human body.
In this study, the researchers created an assay in which cells were infected with the SARS-CoV-2 virus, then exposed to molecules that are produced by human gut microbes. This work revealed antiviral activity in three metabolites that come from bacteria. These molecules are tryptamine, an analog of adenosine, and a disubstituted pyrazine. Notably, these molecules are structurally similar to some synthetic drugs that have already been engineered as a potential treatment for COVID-19, said the study authors.
"It was intriguing that of all the chemistries available, the metabolites we uncovered from the microbiome all bore similarities to clinically-relevant antivirals," said lead study author Frank Piscotta, Ph.D., a postdoctoral researcher at Rockefeller University.
These molecules could, therefore, act as starting points in the development of new antiviral drugs, noted the investigators. The COVID-19 pandemic is still ongoing, and one of the newest treatments to be developed (by Merck) is apparently not as effective as it was first thought; the world needs better treatments for this and other viruses. The researchers suggested that the bacteria that generate these antivirals might also be considered as a therapeutic option.
Now, the researchers are interested in the mechanisms that are underlying the antiviral action of these metabolites, and they want to test the efficacy of the molecules in an animal model. They also want to know whether the severity of a viral infection can be correlated with the level of the bacteria that generate these metabolites; people that are better at fighting off COVID-19 may be carrying high levels of these bacterial molecules.
This study also suggests that scientists should keep exploring the human microbiome to look for other antiviral molecules, added principal study investigator Sean Brady, Ph.D., a professor at Rockefeller University.